1. Field of the Invention
The subject invention is directed to socket drives and, more particularly, socket drives that employ roller clutch mechanisms.
2. Description of the Prior Art
Sockets for turning nuts, bolts, and similar fasteners have found wide acceptance throughout the mechanical arts. They generally permit such fasteners to be turned more easily and quickly and generally cause less wear to the fasteners themselves as compared to other types of wrenches such as adjustable wrenches, box wrenches, and open-end wrenches.
Sockets require a compatible drive mechanism that engages the socket and affords the user a handle by which to apply torque to the socket. To permit the socket to be quickly turned in one direction, socket drives generally provide full torque in one direction and are substantially free-turning in the opposite direction.
Drives known in the prior art have employed various ratchet mechanisms wherein a set of teeth are generally fixed to the handle portion of the drive and a drive mechanism connected to the socket is provided with a number of pawls that engage the teeth. The angular direction in which the pawls engage the teeth is controlled by a selector lever. Examples of such ratchet-type socket drives are shown in U.S. Pat. Nos. 2,570,779; 2,744,432; 2,982,161; 3,044,591; 3,362,267; 3,533,315; 3,881,376; and 4,137,801.
Problems with such ratchet-type drives are primarily the result of the complex mechanical arrangement of the ratchet mechanisms. The ratchet mechanisms often permitted a high degree of play and required close tolerances that made the drives subject to failure caused by mechanical wear. Also, the ratchet mechanisms were too delicate for certain applications and were subject to failure from over-stress. In addition, the designs of the ratchet mechanisms were such that they required a certain threshold countertorque from the fastener and socket before they would ratchet in the opposite direction. When the fastener was sufficiently free to turn so that this threshold countertorque did not develop, the user generally had to supply such force with his free hand. To do this was often inconvenient and awkward and sometimes impossible.
Socket drives have been developed which sought to overcome the disadvantages of the ratchet type drives. Such drives included a type wherein a roller clutch is secured within the cylindrical head portion of a handle and the drive member is concentrically maintained within the roller clutch. The drive member included an extended portion on at least one end for engaging the socket. Examples of roller clutch-type drives are shown in U.S. Pat. Nos. 2,139,650; 3,398,612; and 4,051,935.
Such roller clutch-type drives offered many advantages over ratchet-type drives. They are generally more durable than ratchet-type drives and are able to withstand extreme torque loadings. As another example, ratchet-type drives require that the handle be rotated through at least a given angle before the handle will engage the drive member at a new angle in the torque direction. This sometimes created difficulties when there was minimal space in which the drive could be turned. In reversing the roller clutch-type wrench, there is substantially no minimum angle through which the handle must be turned before the handle will engage the drive at a new angle. As another example of the advantage of roller clutch-type drives, the counter-torque required by the ratchet mechanism of ratchet-type drives was often too great for the fastener to overcome. Thus the fastener and socket would merely rotate in the reverse direction along with the drive handle. In roller clutch-type drives, the counter-torque required is much lower so that reverse rotation of the socket and fastener seldom occurs.
However, the roller clutch-type ratchets known in the prior art shared a significant disadvantage. Namely, such roller clutch-type drives could provide torque in only one angular direction. To provide torque in both directions, extended portions were included on both sides of the drive member or the drive member was mounted such that it could be removed from the cylindrical head and remounted in inverted fashion.
Both these alternatives had disadvantages. Where extended portions were provided from both sides of the drive, the drive was too large for use in many applications. Drives of the type in which the drive member was removed from the cylindrical head and inverted were awkward, time consuming and difficult to use. Accordingly, there was a need in the prior art for a roller clutch-type socket drive that would overcome these disadvantages.